//链表中倒数最后k个结点
public class Solution4 {
    public ListNode FindKthToTail(ListNode head,int k) {
        ListNode fast = head;
        ListNode Low = head;
        if(k<0 || head == null){
            return null;
        }
        int count = 0;
        while(k-1 != count){
            fast = fast.next;
            //处理k太大的问题
            if(fast == null){
                return null;
            }
            count++;
        }
        while (fast.next != null){
            fast = fast.next;
            slow = slow.next;
        }
        return slow;
    }

}